Formula calculation based on pick list values

Formula calculation based on pick list values

Hi There, I am new to using Zoho formulas so thought I would post this here.  I have looked at some posts here but I never seem to understand some of the answers.  Here is what I have write using the INSERT method on the formula builder and I am trying to calculate a TOTAL AMOUNT based on the PREMIUM FREQUENCY and POTENTIALS AMOUNT and the PREMIUM FREQUENCY field is a picklist of values like Weekly, Monthly, Fortnightly etc.

If ${Potentials.Premium Frequency} = Weekly , then ${Potentials.Amount} = ${Potentials.Premium Amount} * 52
Else If ${Potentials.Premium Frequency} = Monthly , then ${Potentials.Amount} = ${Potentials.Premium Amount}* 12

When I try and validate this I always get a Syntax Error for given formula but no indication as to where, I really hope someone cal help.